Mood and sleep in Parkinson's disease.

OBJECTIVE: To determine whether severity of depression and severity of anxiety were associated with particular types of sleep disturbance in patients with Parkinson's disease.
METHOD: 120 patients with a diagnosis of idiopathic Parkinson's disease were consecutively recruited from a movement disorders clinic from July 2004 to May 2005. Idiopathic Parkinson's disease was diagnosed by a board-certified neurologist (J.H.F) and defined by the presence of 3 of the 4 cardinal signs of Parkinson's disease: resting tremor, rigidity, bradykinesia, and postural instability. Patients were administered the Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety, Covi Anxiety Scale, Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS). Patients were assessed for nightmares and rapid eye movement (REM) sleep behavior disorder (RBD) using a structured questionnaire and dream log. Multivariate analyses evaluated whether severity of depression and severity of anxiety correlated with the sleep outcome measures (PSQI, ESS, nightmares, and RBD).
RESULTS: The mean +/- SD age of the patients was 71 +/- 10.8 years with a mean Parkinson's disease duration of 7.3 +/- 4.7 years. Thirty-eight percent were female, 41.7% had a psychiatric history, 53.3% had nightmares, and 30% had clinically defined RBD. Severity of depression and severity of anxiety significantly correlated with poor sleep quality, daytime somnolence, and nightmares. Severity of depression contributed significantly to the overall variance in poor sleep quality and nightmares. Severity of anxiety contributed significantly to the overall variance in daytime somnolence.
CONCLUSIONS: Depressive and anxiety symptoms were associated with sleep disturbances in patients with Parkinson's disease. It is important to examine for the presence of depression and anxiety in patients presenting with sleep disorders, as depression and anxiety impair quality of life and are treatable conditions.